Brazil’s Yanomami indigenous tribe has been complaining of land encroachments by illegal gold miners in the remote rainforest reserve along the Venezuela border.

Brazilian police have arrested at least 26 people in a major operation against illegal gold miners in an Amazon reserve near the border with Venezuela.

The operation was carried out in the Yanomami indigenous reserve, where illegal gold miners were causing serious damage to the environment, police said on Saturday.

Brazilian authorities seized gold, mining equipment and several aircraft used to carry men and supplies into the remote region in Roraima state.

In a year-long investigation, Federal Police identified five criminal groups involved in illegal gold mining in the state, where the indigenous Yanomami population has long complained of miners entering their lands.

The mining gangs cause significant damage by using powerful pumps on ships to dredge material from the river bed and blast the river banks, as well as using highly-toxic mercury to separate gold from the river silt.

Police said the operation was aimed at stemming illegal mining by arresting the financiers — including pilots, engineers and businessmen — and confiscating the aircraft used for the incursions into indigenous lands.

Around 20,000 Yanomami live in relative isolation in the remote indigenous reserve, which covers nearly 100,000 square km of rainforest along the Venezuelan border.

The forest-dwelling people have been resisting land invasions by gold miners for decades, accusing them of destroying the rainforest and spreading diseases.